Severe Storm Risk - Yellowstone National Park, WY

There is a Marginal Severe Storm Risk for your location. Continue reading for today's outlook from the National Weather Service's Storm Prediction Center. -------------------- National Severe Storm Outlook THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS PORTIONS OF CENTRAL AND SOUTHERN TEXAS SUMMARY Isolated to scattered severe thunderstorms are possible this afternoon and evening across parts of the southern High Plains. More isolated severe storms will be possible across portions of the Upper Great Lakes and northern Rockies. Synopsis Early-morning surface observations reveal a surface low developing across the northern High Plains with a broad fetch of southerly flow from the western Gulf into the Plains and Midwest. This broad warm sector characterized by mid 50s to low/mid 60s dewpoints will largely remain in place through the day as the surface low translates east across the Plains into the Great Lakes region tonight. The greatest potential for strong/severe thunderstorms will reside within this warm sector where regional forcing for ascent will support a chance for deep convection. Southern Plains Latest 00z HREF/REFS guidance, as well as more recent CAM solutions, all show considerable variability in the evolution of an ongoing MCS through late morning across southern/southeast TX. While most solutions depict a steady weakening trend, others - notably the WRF-ARW - hint at some continued wind threat across the TX Coastal Plain this morning. Regardless, this activity is forecast to diminish by late morning/early afternoon, and will likely leave an outflow boundary on the western periphery of the cold pool in its wake. Dewpoints in the low to mid 60s will quickly return northward in the wake of the MCS with ensemble guidance depicting a plume of MLCAPE values between 1500-2000 J/kg from central TX into western OK by mid-afternoon. Thunderstorm development appears possible along any residual outflow boundaries across central TX given weak capping depicted in forecast soundings, though confidence in precisely where this will occur or how widespread storm coverage will be remains fairly uncertain. Thunderstorm initiation off the Sierra Del Carmen mountains in northern Mexico and along a weak dryline across southern KS southward into western OK/TX appears more probable, though again, storm coverage will likely remain fairly isolated given weak forcing for ascent and some degree of synoptic-scale subsidence in the wake of the upper disturbance currently passing over the region. Convection that can develop within this buoyant and weakly capped environment could become fairly intense given favorable thermodynamic profiles. Despite some mid-level backing in forecast hodographs, effective bulk shear values appear sufficient for a large, to perhaps very large hail threat. However, given the aforementioned uncertainties in thunderstorm coverage, 15% hail probabilities have been confined to where ensemble guidance depicts the best overall convective signal. Minnesota A lee cyclone evident in recent surface observations over the northern High Plains will migrate eastward along the U.S./Canaidan border through the day, reaching northern MN by around peak heating. A narrow tongue of returning moisture may support a corridor of sufficient ascent and buoyancy for deep convection. While latest guidance remains somewhat mixed on thunderstorm coverage, forecast soundings suggest elevated convection may support a threat for large hail. Furthermore, several high-res forecast soundings depict an environment favorable for surface-based supercells along the frontal zone where dewpoints may reach into the mid/upper 50s. While this potential appears very low per recent ensemble guidance, some tornado threat could materialize along the front where STP values of 1-2 may emerge. Northern Rockies A plume of mid-level moisture (PWATs between 0.4 to 0.5 inches) was recently observed in regional 00z RAOBs across the Great Basin region. This air mass will largely remain in place over the next 24 hours ahead of an approaching upper low out of northern CA. This mid-level moisture will support another day of fairly modest surface-based buoyancy (around 250-500 J/kg SBCAPE), but persistent 30-40 knot flow within the CAPE-bearing layer combined with somewhat deep boundary-layer mixing (LCLs forecast to be around 2 km) may support another day of strong to severe downburst winds with the more robust convective cells.